There are hard encounters for tanks, dps and healers. In a tank and spank fight, all roles are equally easy, and don't take too many hours to perform them within a point where your luck and gear does more for you than your occasional mistake.

For example, t13 was horribly easy and boring to tank. In t14 Blizzard has put more on the plate of tanks again, and I would say that this tier is harder as tank than as dps. I don't have input on healing. T15 could be harder to dps than to tank again, who knows.

In my experience, tanking has less to do with gear and rotations. It's more about control of mobs, abilities, and actively reducing large damage abilities.

And you don't think DPS can mindlessly spam a "rotation" to be mediocre? Interesting point of view.

Tanks are largely about their gear - because dodge parry block armor and other stuff are passive. It became bit more active in panda but if you see Cata prot pally or feral they were seriously gear reliant.
The active tanking stuff made things more harder, making tanks do rotations. Yet it still is easier than DPS

And controlling mobs isn't too hard since 500% aggro patch - It is impossible to lose aggro to DPS.

And about DPS? I saw people spam rotations and see boss go berserk so many times...

There are exceptions where tanks are harder(Fights like Nefarian and stuff), but most fights doesn't really require that much tank focus.

Um also tanks are usually free from burden of meters and therefore could concentrate in other stuff

Tanking is very reactive. Once you get that initial threat almost everything else is in reaction to the situation. Even the positioning of bosses and mobs is in reaction to a mechanic or attack.

Healing is the middle ground of reacting to damage being done and keeping players within a certain hp range. Except for rare mechanics having players at 100% hp is always a good thing.

Dps feel very proactive. As long as the dps watch their threat they have very little reason to hold back. They can force the boss to change phases with the right amount of damage and even extend a phase until the time is right to get the maximum buff to their damage.

Having experience with both, my vote goes to DPSing as the more demanding role.

As a tank you can max out your performance and still have plenty of room in your head to check on the whole raid and everything else going on. As a good DPS that takes the least amount of damage while dishing out the most you are far more occupied and busy.

1. Tanking is largely passive. Avoid/parry/block/etc is huge portion of tanking, and they all happen automatically.
In contrast for DPS autoattacks are really small part of dps.

2. Losing aggro is impossible nowadays - with 500% patch it's just plain impossible to do so. Maybe holding aggro of sudden burst of adds might be issue but usually DPS will be required to not attack until tank could hold aggro to some degree

3. Tanks are usually free of meters. If something goes berserk then it's DPS' fault. Again some exceptions when everyone is undergeared or tanks are primary DPSers (Alysrazor for example)

4. If tanks screw up healers can cope with it. If DPS makes mistakes then that's gone.

5. Cooldowns - Tank cooldowns are passive; you press button, get ~% reduction, and you don't have to worry about it.
DPS have to dps extra harder during cooldowns, or change their rotation and stuff

6. In most fights boss positioning isn't hard at all - And infrequently required to change in most fights

I have done all three and personal thoughts

DPS is hardest by difficulty
Healing is most burdening
Tank is usually faceroll with few exceptions depending on the fight

I disagree wholeheartedly with this. First, no one in your raid should be going AFK, even in trash clears, and no one should be late or missing raids. Those kind of players should be replaced.

Besides few hundreds of hardcore guilds there are thousands and thousands of mediocore and casual guilds. Where kicking players for afk, being late and missing raids because of irl activities is considered more than acceptable.

Also I don't know about you, but I personally played in one of the top25 guilds and we did not kick any single person from guild for going afk during trash. You know, we all have our human needs.

Secondly, DPS is not "do your rotation and move from fire". There are encounters that require divided or specific amounts of damage done, everyone to group up in specific arrangements to chain or otherwise split damage, and fights that specify group movements in and out of other zones in order to complete the fight successfully.

You are talking about basic encounter mechanics that are the same for all people in raid. Why would you think that dps should be different from others? And yes, depanding on arrangements and particular boss the fight can be harder for tank, healer or dps.
Its just in average the tanks job is harder and more responsible.

DPS are not easily replaced.

Yes they are. In good hardcore guilds you have 5-10 players sitting on the bench.
In casual guilds there is no real difference what dps to take. You can take alt character or healer with dps spec. You can even take a pug. Or you can just go and kill the boss with 9.

The best tanks and healers in the world are nothing without the DPS to back them up and bring down the boss.

And why did you made this ridiculous assumption?

You just need to play both roles long enough to understand the difference.
On our Ragnaros 25H first kill one of our dps died 3 times and was ressed twice, and it still was enough to make transition to p4 and kill him. We did the spine of deathwing 25hc pre-nerf(and I mean tendon nerf) without 1 dps because he was stupid enough to fail on barrel roll in the middle of the fight.

When you have bosses on farm as dps you can basically just go afk at the beginning of the fight, come back in 5 minutes, say "Sorry, disconnect, res me. I need this item btw". As tank you just can't do this. You have responsibility.

All the tanks I know that switched to dps say the same "omg, its so much less stressful and more fun to play dps!". And its true.

I both tank and dps, and I must say that most of the time dps-ing is the hardest. There is fights where tanking is a lot harder but most of the time if I screw something up with the rotation nobody will notice, actually on some fights you can without any problem alt-tab out from the game for short moments to do other things have done i myself many times and I was watching a raiding stream on twitch recently, tank PoV, where he regularly alt-tabed out from the raid boss fight, browsing facebook, chatting with a friend on skype and posting links to his stream.

But as a dps if I just lose focus for a second I will see myself moving down on the meters and lose my chance to rank and everyone in the raid will know that I was slacking and my stats on logs and ranks will look like I'm an worse player then I really am.

When tanks and healers are doing their job well, dpsing is easy. When tanks and healers are failing and I'm having to move to awkward places to accommodate poor positioning, using heals instead of damage dealing abilities to compensate for lack of healing output to normal, unavoidable damage, or find myself having to use survival moves, abilities, or just holding back/vanishing/shadowmelding because I keep eclipsing tank threat while dealing damage, it makes dpsing hard and makes dealing proper damage difficult. All the same when DPS aren't pulling for you as tank or not standing in fire for healers, it makes their jobs easier. It's an equilibrium really

Yes, mocking up the rotation in the expansion of hit/exp capping 70 kdps tanks which defenses come from said rotation doesn't matter at all as a tank. Let's afk and let passive avoidance do its magic on 160k hit you in the face bosses, and some dps take up the 30kdps difference between a bad a good tank.

The counterpoint to your argument is that the tanks and healers have to do all this as well, so the only difference is that the dps has to execute his priority list/rotation while dancing. The tank has to stay alive, manage aggro and switches, and position the boss, the healers have to prepare for special attacks and damage phases, etc.

The point being that if the tank or healers screw up, a wipe is much more likely, and much sooner, than if a dps is slow, or dies due to a mistake.

Of course, dps is crucial to party and raid composition, and the better the dps, the faster the fight, which is good, especially if your dps are all solid. I think, and this wasn't clear in the OP's opening, there is a huge difference between what I'll call hardcore raiding and regular play. At the high end, some dps classes can be quite challenging. At regular levels of play (say off spec frost dk) you can spam three buttons and be near the top of the charts as long as your gear is ok.

Not necessarily. I've watched us wipe on Elegon because just one dps died in a crucial phase (between 3 - 4 stacks of Draw Power) and that meant not reaching the enrage timer. Granted, more gear = more dps = more time and ability to make mistakes. You are right that more often a wipe is a wipe if the tank or healer dies, true. But that doesn't trivialize DPS.

Originally Posted by traen

Besides few hundreds of hardcore guilds there are thousands and thousands of mediocore and casual guilds. Where kicking players for afk, being late and missing raids because of irl activities is considered more than acceptable.

Also I don't know about you, but I personally played in one of the top25 guilds and we did not kick any single person from guild for going afk during trash. You know, we all have our human needs.

Well I'll counter that while that stuff is fine, I'm referring to people who are constantly late or AFK. His implication was that DPS was so easy that you could just sleep through trash and show up late and everything is fine no matter what. Most guilds are fine with the occasional human needs. They're not okay with slacking.

Originally Posted by traen

You are talking about basic encounter mechanics that are the same for all people in raid. Why would you think that dps should be different from others? And yes, depanding on arrangements and particular boss the fight can be harder for tank, healer or dps.
Its just in average the tanks job is harder and more responsible.

I still disagree. There are fights specifically that are difficult only for the DPS and/or healers. Baleroc, for example, on which I was a 25 man MT. My job? Just taunting on Decimation and hitting my avoidance cooldowns (avoidance rocked on that fight). DPS? They had to swap groups on crystals, avoid being nearing each other to keep from spreading, take stacks and rotate cooldowns/rezzes (in case anyone did die), and healers had to stack their healing buff for the tanks. That's just one example.

Now, I'm not saying that tanks never have it hard or healers never have it hard. My point was that all 3 roles have it hard at times, depending on the fight. To blanket DPS as the role where it's always easy is wrong.

Originally Posted by traen

Yes they are. In good hardcore guilds you have 5-10 players sitting on the bench.
In casual guilds there is no real difference what dps to take. You can take alt character or healer with dps spec. You can even take a pug. Or you can just go and kill the boss with 9.

The vast majority of players are not in serious hardcore guilds. We had 28 people, sometimes 29, that signed up for raid every week. I remember in my 10 man guild having to pug someone nearly every week. I even still sometimes fill in for another 10 man guild right now because they can't always fill the roster.

Originally Posted by traen

And why did you made this ridiculous assumption?

You just need to play both roles long enough to understand the difference.
On our Ragnaros 25H first kill one of our dps died 3 times and was ressed twice, and it still was enough to make transition to p4 and kill him. We did the spine of deathwing 25hc pre-nerf(and I mean tendon nerf) without 1 dps because he was stupid enough to fail on barrel roll in the middle of the fight.

When you have bosses on farm as dps you can basically just go afk at the beginning of the fight, come back in 5 minutes, say "Sorry, disconnect, res me. I need this item btw". As tank you just can't do this. You have responsibility.

All the tanks I know that switched to dps say the same "omg, its so much less stressful and more fun to play dps!". And its true.

I did exactly that. I was a main tank (DK) from Ulduar to Dragon Soul. In Dragon Soul I took a break for tanking and switch to DPS. You know what? It wasn't harder or easier. Instead of managing my aggro (that went out the window in 4.1) and my damage reduction cooldowns I switched to maximizing my pre-pull damage and avoiding taking any while keeping my dps as competitive as possible. It carries it's own stresses.

I like how you tried to tear apart what I said but you missed the context. I wasn't saying DPS is insanely hard, I was saying that you can't just generalize dps as an easy-at-all-times role that is brainless.